Log Select (4C) - IBM DDRS-39130 - Ultrastar 9.1 GB Hard Drive Specifications

7.7 LOG SELECT (4C)

Byte
7 6
0
1 LUN
2 PC
3
4
5
6
7 (MSB)
8
9
Figure 65. L O G SELECT (4C)
The LOG SELECT command provides a means for the initiator to clear statistical information maintained
by the drive and reported via the Log Sense command.
PCR The Parameter Code Reset determines whether the Log Sense parameters will be cleared and unit
attention posted for all other initiators. A value of 1 indicates that the parameters should be cleared,
while a value of zero (except when PC = 11b) indicates that the parameters should not be cleared.
SP The Save Parameters bit value of zero indicates that the page parameters not be saved. A value of 1
indicates that the page parameters that are saveable should be saved after they have been changed.
PC The Page Control field defines the type of parameters to be selected. The PC field set to 11b (and
P C R is then a don't care) indicates that the Default Cumulative values are set to their default values of
0. If the PC field is set to 01b and P C R is set to 1 the Current Cumulative values are also set to their
default values.
As the file does not support the threshold pages any other value in this field will cause the command to
end with a CHECK CONDITION with a sense key of illegal request and an additional sense code of
invalid field in CDB.
Parameter List Length The Parameter List Length must be zero to indicate that no data is transferred
from the initiator to the target during the potential DATA O U T phase.
If one or more fields of the CDB are not set correctly the command will be terminated with a CHECK
CONDITION status. The Sense Key shall be set to Illegal Request and the additional sense code set to
Invalid Field in CDB.
The Log Select command will reset the counter variables to their default values of zero. These variables are
listed in the Log Sense command.
The target generates a unit attention condition, to indicate that parameters have changed, for all initiators
except the one that issued the Log Select command.
76
O E M Spec. of DDRS-3xxxx
Bit
5 4 3
Command Code = 4Ch
Reserved = 0
Reserved = 0
Reserved = 0
Parameter List Length = 0
Reserved = 0
2 1 0
PCR SP
(LSB)
FLAG LINK